Traffic Steering (Policy-Based Routing)

Policy-Based Routing (PBR) enables forwarding decisions based on multiple criteria beyond destination IP address alone. Unlike traditional routing that matches only the destination address, PBR matches source/destination addresses, applications, ports, and traffic flows to direct packets to specific next-hops or interfaces.

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Overview

What PBR Does

By default, a router examines packet destination addresses and forwards them through the routing table (static routes or dynamic routing protocols like OSPF/BGP). This works well for most scenarios, but complex deployments require more granular control.

PBR allows you to:

• Route traffic from specific source networks through different ISP links
• Send application traffic (HTTP, HTTPS, etc.) to different gateways
• Redirect traffic to external proxies, firewalls, or caching engines
• Implement failover policies when primary paths fail

How It Works

PBR operates as a first-pass filter before the standard routing table:

1. Packet arrives at inbound interface
2. Router checks if it matches any PBR policy
3. If matched: Forward using PBR next-hop (higher priority)
4. If not matched: Consult routing table (including default route)
5. If still no match: Drop packet

This prioritization ensures PBR rules take precedence over standard L3 routing.

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Use Cases

Scenario	Benefit
Multi-ISP Load Balancing	Route different client networks or applications through separate ISP links to balance traffic and avoid congestion
Application-Specific Routing	Send video streaming through a high-bandwidth ISP; email through a low-cost ISP
Failover Policies	Automatically route traffic through backup ISP when primary path fails
Interconnecting Private Networks	Direct traffic between branch offices through specific VPN tunnels
Compliance Routing	Route sensitive traffic through approved gateways or DLP proxies

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Requirements

• Firmware: RansNet OS with PBR support
• Interfaces: Minimum 2 WAN links or multiple local networks
• Routing: At least one default route configured per ISP/nexthop
• For packet flow matching: Firewall marking feature is used

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Configuration Methods

Traffic Matching Options

RansNet PBR supports three primary matching methods:

Method	Criteria	Use Case
By Source/Destination Address	Source IP/network, Destination IP/network	Different client networks → different ISPs
By Packet Flow	Protocol, port, FQDN, application objects	HTTP/HTTPS/DNS → different gateways
By Existing Policy	Inherit from an existing rule for backup routes	Same traffic → different gateways

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Configuration Example 1: Routing by Source Network

Scenario

Route clients from 172.16.30.0/24 through ISP-1 (eth0) and clients from 172.16.40.0/24 through ISP-2 (eth1).

Topology

Topology Summary:

WAN Links (ISP Connections):

The RansNet router sits at the center with two WAN links:

• ISP-1 link (eth0): Connected to ISP-1 Router at 172.16.10.1/30 (your device is 172.16.10.2/30)
• ISP-2 link (eth1): Connected to ISP-2 Router at 172.16.20.1/30 (your device is 172.16.20.2/30)

Local Networks (Client LANs):

Two local networks are connected to the RansNet router:

• LAN-1 (eth2): PC1 in subnet 172.16.30.0/24 — traffic will route through ISP-1 (eth0)
• LAN-2 (eth3): PC2 in subnet 172.16.40.0/24 — traffic will route through ISP-2 (eth1)

Traffic Flow:

This setup ensures that regardless of destination, all traffic from PC1 exits through ISP-1 and all traffic from PC2 exits through ISP-2.

Configuration

GUI Configuration

Navigate to Device Settings → SD-WAN → Traffic Steering and click Add Policy.

Step 1: Configure First Policy (LAN-1 → ISP-1)

Fill in the following fields:

Field	Value	Description
Policy No.	100	Unique identifier for this policy (range 100–199). Lower numbers are evaluated first.
Nexthop IP/Interface	eth0	The WAN interface through which traffic matching this policy will be routed.
Traffic Matching Options	By Networks	Select how packets are matched: By Networks (source/destination IP), By Packet Flow (protocol/port), or By Existing Policy.
Networks	Source Network	Enable source network matching to route based on the origin subnet.
Source Network	172.16.30.0/24	The LAN subnet whose traffic should be routed through eth0. Packets from PC1 (172.16.30.x) match this policy.

Click Continue to proceed.

Step 2: Configure Second Policy (LAN-2 → ISP-2)

Click Add Policy again and repeat with these values:

Field	Value
Policy No.	101
Nexthop IP/Interface	eth1
Traffic Matching Options	By Networks
Source Network	172.16.40.0/24

Then click Save and Apply Config to activate both policies.

CLI Configuration

!
interface eth0
 enable
 ip address 172.16.10.2/30
!
interface eth1
 enable
 ip address 172.16.20.2/30
!
interface eth2
 enable
 ip address 172.16.30.1/24
!
interface eth3
 enable
 ip address 172.16.40.1/24
!
ip route 0.0.0.0/0 nexthop 172.16.10.1 remark ISP-1
ip route 0.0.0.0/0 nexthop 172.16.20.1 remark ISP-2
!
firewall-access 100 permit outbound eth0
firewall-access 101 permit outbound eth1
!
firewall-snat 100 overload outbound eth0
firewall-snat 101 overload outbound eth1
!
!define policy ID to match packets by source subnets
ip pbr policy 100 src 172.16.30.0/24
ip pbr policy 101 src 172.16.40.0/24
!
!apply specific forwarding/routing rule based on pre-defined policy ID
ip pbr 100 nexthop eth0
ip pbr 101 nexthop eth1
!

Verification

Items to Test	Command	Expected Outcome
PBR Policies Active	show ip pbr policy	Shows policy 100 and 101 with source networks defined
PBR Routes Installed	show ip pbr	Shows routes 100 and 101 with eth0/eth1 as nexthops
LAN-1 Client Routing	From 172.16.30.x: traceroute 8.8.8.8	Route passes through eth0 (ISP-1 gateway 172.16.10.1)
LAN-2 Client Routing	From 172.16.40.x: traceroute 8.8.8.8	Route passes through eth1 (ISP-2 gateway 172.16.20.1)

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Configuration Example 2: Routing by Packet Flow (Application-Based)

Scenario

Route application traffic (HTTP, HTTPS) from client networks through different ISPs based on protocol:

• HTTP/SMTP traffic (TCP/80, TCP/25) → ISP-1
• HTTPS traffic (TCP/443) → ISP-2

This allows fine-grained control: you might send bandwidth-heavy video traffic (HTTPS) through a premium ISP while routing email (SMTP) through a cost-effective link.

Configuration

GUI Configuration

Navigate to Device Settings → SD-WAN → Traffic Steering and click Add Policy.

Step 1: Configure HTTP Policy (TCP/80, TCP/25 → ISP-1)

Fill in the following fields:

Field	Value	Description
Policy No.	100	Unique policy identifier.
Nexthop IP/Interface	eth0	Route HTTP/SMTP to ISP-1.
Traffic Matching Options	By Packet Flow	Match based on protocol and port instead of source IP.
Inbound Interface	eth2	Apply this rule to traffic arriving on the LAN-1 interface.
Protocol	TCP	Match TCP protocol (HTTP and SMTP both use TCP).
Destination Port	80,25	Match HTTP (port 80) and SMTP (port 25). Use comma to separate multiple ports.

Click Continue, then Save and Apply.

Step 2: Configure HTTPS Policy (TCP/443 → ISP-2)

Click Add Policy again and repeat with these values:

Field	Value
Policy No.	101
Nexthop IP/Interface	eth1
Traffic Matching Options	By Packet Flow
Inbound Interface	eth2
Protocol	TCP
Destination Port	443

Note

Packet flow matching is applied at inbound interfaces. If you have multiple LANs with different routing requirements, repeat the rule on each inbound interface (eth2, eth3, etc.).

For LAN-2 (eth3): Repeat Steps 1 and 2, but change Inbound Interface to eth3 and use Policy No. 102 and 103.

CLI Configuration

ip pbr policy 100 fwmark 100 remark "PC1 traffic to tcp 80/25"
ip pbr policy 101 fwmark 101 remark "PC2 traffic to tcp 80/25"
ip pbr policy 102 fwmark 102 remark "PC1 traffic to tcp/443"
ip pbr policy 103 fwmark 103 remark "PC2 traffic to tcp/443"
!
ip pbr 100 nexthop eth0 remark "PC1 traffic to tcp 80/25"
ip pbr 101 nexthop eth0 remark "PC2 traffic to tcp 80/25"
ip pbr 102 nexthop eth1 remark "PC1 traffic to tcp/443"
ip pbr 103 nexthop eth1 remark "PC2 traffic to tcp/443"
!
firewall-set 100 mark 100 inbound eth2 tcp dport 80,25 remark "PC1 traffic to tcp 80/25"
firewall-set 101 mark 101 inbound eth3 tcp dport 80,25 remark "PC2 traffic to tcp 80/25"
firewall-set 102 mark 102 inbound eth2 tcp dport 443 remark "PC1 traffic to tcp/443"
firewall-set 103 mark 103 inbound eth3 tcp dport 443 remark "PC2 traffic to tcp/443"
!

Verification

Items to Test	Command	Expected Outcome
Firewall Rules Applied	show firewall-set	Shows marks 100, 101, 102, 103 matching on respective interfaces
PBR Routes Loaded	show ip pbr	Shows PBR routes 100, 101, 102, 103 with correct nexthop
HTTP Traffic Path	From LAN: curl -v http://example.com	Connection originates from ISP-1 (eth0)
HTTPS Traffic Path	From LAN: curl -v https://example.com	Connection originates from ISP-2 (eth1)

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Configuration Example 3: PBR Failover

Scenario

Extend Example 2 to add automatic failover: if ISP-2 fails, HTTPS traffic automatically routes through ISP-1 backup link.

Option 1: Track Link Default Routes (Simpler)

We configure tracking for the ISP2 default route. When ISP2 link fails, the default route for ISP2 to 172.16.20.1 (via eth1) will be withdrawn.

!
ip route 0.0.0.0/0 nexthop 172.16.10.1 remark ISP-1
ip route 0.0.0.0/0 nexthop 172.16.20.1 track icmp 172.16.20.1 60 remark ISP-2
!

When the default route to ISP-2 is withdrawn, PBR rules using nexthop eth1 automatically disappears. Remaining traffic falls back to ISP-1 default route.

ip pbr 100 nexthop eth0 remark "PC1 traffic to tcp 80/25"
ip pbr 101 nexthop eth0 remark "PC2 traffic to tcp 80/25"
!below PBR routes will stop working once the eth1 nexthop (default route) is gone.
ip pbr 102 nexthop eth1 remark "PC1 traffic to tcp/443"
ip pbr 103 nexthop eth1 remark "PC2 traffic to tcp/443"

Pros: Simple, no extra configuration
Cons: Relies on understanding routing table dependency

Option 2: Track PBR Routes Directly (Recommended)

Create explicit backup PBR routes that activate when primary tracking fails. This approach gives you finer control: different traffic types can have different failover behaviors.

Setup Overview:

• Primary policies (102, 103): Route HTTPS to ISP-2 with tracking enabled
• Backup policies (104, 105): Route HTTPS to ISP-1 only when primary policies fail
• When ISP-2 link is active, policies 102/103 handle HTTPS traffic
• When ISP-2 link fails, policies 102/103 are withdrawn and policies 104/105 automatically activate, redirecting HTTPS to ISP-1

GUI Configuration for Failover Policies

Navigate to Device Settings → SD-WAN → Traffic Steering and create the following:

Primary Policies (Route HTTPS to ISP-2 with Tracking):

Policy No.	Traffic Match	Nexthop	Tracking	Notes
102	TCP/443 from eth2	eth1	track icmp 172.16.20.1 60	PC1 HTTPS → ISP-2, monitored
103	TCP/443 from eth3	eth1	track icmp 172.16.20.1 60	PC2 HTTPS → ISP-2, monitored

Backup Policies (Route HTTPS to ISP-1 as Fallback):

Policy No.	Traffic Match	Nexthop	Tracking	Notes
104	Same as 102 (reuse)	eth0	No	PC1 HTTPS → ISP-1 fallback
105	Same as 103 (reuse)	eth0	No	PC2 HTTPS → ISP-1 fallback

When configuring Policy 104, select Traffic Matching Options: By Existing Policy and reference Policy 102. This ensures 104 matches the same traffic as 102 but routes through a different nexthop.

ip pbr policy 100 fwmark 100 remark "PC1 traffic to tcp 80/25"
ip pbr policy 101 fwmark 101 remark "PC2 traffic to tcp 80/25"
ip pbr policy 102 fwmark 102 remark "PC1 traffic to tcp/443"
ip pbr policy 103 fwmark 103 remark "PC2 traffic to tcp/443"
!PRB policies matching the same traffic for tcp/443 via ISP1 (reuse existing policy)
ip pbr policy 104 fwmark 102 remark "PC1 traffic to tcp/443 (fall back to ISP1)"
ip pbr policy 105 fwmark 103 remark "PC2 traffic to tcp/443 (fall back to ISP1)"
!
ip pbr 100 nexthop eth0 remark "PC1 traffic to tcp 80/25"
ip pbr 101 nexthop eth0 remark "PC2 traffic to tcp 80/25"
!when tracking fails, pbr 102 and 103 will withdraw
ip pbr 102 nexthop eth1 track icmp 172.16.20.1 60 remark "PC1 traffic to tcp/443"
ip pbr 103 nexthop eth1 track icmp 172.16.20.1 58 remark "PC2 traffic to tcp/443"
!tcp/443 traffic will follow routes to ISP1
ip pbr 104 nexthop eth0 remark "PC1 traffic to tcp/443 (fall back to ISP1)"
ip pbr 105 nexthop eth0 remark "PC2 traffic to tcp/443 (fall back to ISP1)"
!
firewall-set 100 mark 100 inbound eth2 tcp dport 80,25 remark "PC1 traffic to tcp 80/25"
firewall-set 101 mark 101 inbound eth3 tcp dport 80,25 remark "PC2 traffic to tcp 80/25"
firewall-set 102 mark 102 inbound eth2 tcp dport 443 remark "PC1 traffic to tcp/443"
firewall-set 103 mark 103 inbound eth3 tcp dport 443 remark "PC2 traffic to tcp/443"
!

How it works:

1. HTTPS traffic (fwmark 102/103) matches both policy 102/103, and policy 104/105
2. PBR route 102/103 is evaluated first (lower rule number)
3. When ISP-2 tracking succeeds, traffic routes via eth1
4. When ISP-2 tracking fails, route 102/103 are withdrawn
5. Traffic then matches routes 104/105 via eth0 (ISP-1 backup)

Pros: Explicit, flexible, allows different failover actions per policy
Cons: Requires understanding policy evaluation order

Verification

Items to Test	Command	Expected Outcome
ISP-2 Active	show ip pbr	PBR routes 102/103 show nexthop eth1 active
ISP-2 Failed	Disconnect ISP-2, wait 60s; show ip pbr	PBR routes 102/103 withdrawn, routes 104/105 active (eth0)
Failover Tested	traceroute 8.8.8.8 (during failure)	Packets now originate from ISP-1 (eth0)
Track Status	show ip route tracking	ISP-2 track shows "DOWN" when failing

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Configuration Example 4: PBR with Hotspot Networks

When Hotspot service is enabled, client traffic arrives through dynamic tunnel interfaces (tun0, tun1, etc.). Since tunnel IDs are auto-assigned, match using tun+ wildcard combined with source IP/network to differentiate clients.

!
firewall-set 100 mark 100 inbound tun+ tcp src 172.16.30.0/24 dport 80,25 remark "PC1 traffic to tcp 80/25"
firewall-set 101 mark 101 inbound tun+ tcp src 172.16.34.0/24 dport 80,25 remark "PC2 traffic to tcp 80/25"
firewall-set 102 mark 102 inbound tun+ tcp src 172.16.30.0/24 dport 443 remark "PC1 traffic to tcp/443"
firewall-set 103 mark 103 inbound tun+ tcp src 172.16.30.0/24 dport 443 remark "PC2 traffic to tcp/443"
!

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Important Notes

Warning

PBR Rule Evaluation Order
Rules are evaluated sequentially by rule number (lowest first). Once a packet matches a rule, that rule is applied and evaluation stops. Avoid overlapping rules across different policies, as only the first match takes effect.

Avoid Overlapping firewall-set Rules

firewall-set rules are evaluated in ascending rule number order. Each matching rule overwrites the fwmark set by any previous rule — the last matching rule wins. If two rules can match the same packet, that packet will always be marked by the higher-numbered rule, overriding the intended policy.

Example: If rule 100 marks tcp dport 443 (HTTPS) for policy 100, and rule 105 marks a broader pattern (e.g., social media destinations) that also includes HTTPS traffic, then all HTTPS traffic to social media sites will be marked 105 and routed by policy 105 — not policy 100 as intended. To avoid this, ensure firewall-set rules are mutually exclusive: no packet should match more than one rule.

Tip

Nexthop Configuration
When setting nexthop as an interface (e.g., eth0), ensure that interface has a default route with an explicit gateway IP. The system automatically learns the gateway as the nexthop IP. Otherwise, configure gateway IP as the nexthop.

Note

Hotspot + PBR Interaction
Due to order of operations, when PBR is enabled on Hotspot gateways:

• Use "By Packet Flow" matching (not source IP matching)
• Always match on tun+ inbound interface
• Combine with source IP/network to target specific clients
• Avoid direct ip pbr policy src on hotspot networks (packets won't match due to tunnel encapsulation)

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Best Practices

General Deployment

• Start Simple: Begin with source network-based routing (Example 1) before adding packet flow complexity
• Document Policies: Add remarks to each policy and route rule explaining its purpose
• Test Failover: Manually test backup routes by disconnecting primary links before deploying to production
• Monitor Tracking: Regularly check show ip pbr and show logging system to ensure health checks are functioning (turn on log option in your tracking config)

Firewall Rules & Marking

• Consistent Marking: Use a consistent marking scheme (e.g., 100s series for policy A, 110s series for policy B)
• Use Named Objects: Reference firewall objects (protocol groups, FQDN groups) rather than hardcoding ports
• Avoid Overlaps: Each packet should match exactly one firewall-set rule to prevent unexpected behavior.

Performance & Scaling

• Policy Count: Tested with 20+ active policies; scale depends on traffic volume and hardware
• Bandwidth Impact: PBR adds minimal overhead (packet inspection at inbound interface only)

High-Availability Scenarios

• Tracking Intervals: Use 60-second intervals for geographically distributed links; 30 seconds for local redundancy
• Redundant Health Checks: It needed, it's supported to use both ICMP tracking (on default routes) and PBR tracking (on policies) for defense-in-depth
• Backup Routes: Always define fallback routes for critical traffic; use Option 2 (explicit backup policies) for mission-critical failover

Security Best Practices

• Access Control: Combine PBR with firewall policies to restrict sensitive traffic to specific gateways (e.g., corporate proxy)
• Logging: Enable firewall logging on marking rules to audit which traffic is subject to PBR
• Management Access: Never route management traffic (SSH, GUI) through external gateways; ensure management traffic uses default routing or a trusted ISP only

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Troubleshooting

Symptom	Likely Cause	Solution
Traffic not matching PBR policy	Source address doesn't match policy condition; or packet arrives on unexpected interface	Verify source IP in traceroute matches policy definition. Check show ip pbr to confirm rule is installed.
Packets fall back to default route	PBR policy installed but no matching next-hop (interface is down or has no default route)	Verify interface status with show interface. Confirm default route exists: show ip route default. Check PBR nexthop with show ip pbr
Failover not occurring	Tracking not configured, or tracking health check is incorrect	Verify ip pbr ... track command on primary route. Check tracking status: show ip pbr. Test health check manually: ping <tracked-address> from router
Firewall-set not matching	Rule has wrong inbound interface; or source/destination doesn't match (hotspot tunnel confusion)	Verify inbound interface with show firewall set-list detail. For hotspot, use tun+ wildcard, not specific eth interfaces. Check source IPs are within matching network
PBR policies applied but no effect	Route is installed but nexthop interface is down; or policy has lower priority than routing table entry	Verify interface is UP: show interface <nexthop-interface>. Confirm policy evaluates before routing table (PBR always has priority). Check for overlapping firewall-set rules causing unexpected matches

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Related Features

• Static Routes — Configure default routes for each ISP link
• Tracking Configuration — Health monitoring for automatic failover
• Firewall Policies — Deep-packet inspection for flow matching
• Traffic Shaping (QoS) — Combine with PBR for bandwidth management per policy